My Account

Statistics

The role of bacteriophage in granulation

Author

Tay, Martin Qi Xiang

Date of Issue

2013

School

School of Biological Sciences

Related Organization

SCELSE

Abstract

Aerobic granulation technologies are important in water reclamation processes due
to their capability to remove nutrient and toxins efficiently. The formation of
granules has traditionally been done by selection through physical parameters,
such as hydrolic retention time and shear force. However this selection is done
without a clear understanding of how the selection works. Granules represent a
suspended biofilm for which the developmental stages have been shown to be
analogous to that of surface associated biofilms. The aim of this thesis is to
investigate the role of bacteriophage in granular systems, in attempt to create a
better understanding in its developmental process. A multi-pronged approach was
used to tackle this challenge, Pf phage and Pseudomonas aeruginosa was used the
model to establish a better understanding of phage-host interactions during biofilm
development and a granulation reactor will be operated to allow for the monitoring
of virus production and the study of the viral community shift with respect to the
different phases of granular development.
Results from the transcriptomic analyses of the ΔPf4 mutant revealed the up
regulation of genes from the filamentous phage correlates to the up regulated of
genes essential for variant formation, biofilm development and virulence. Phage
population dynamics experiments carried out in this study also demonstrated that
the Pf4 phage has a suppressive effect on a secondary prophage (Pf6). The
metagenomics study of the viral fraction allowed for reconstruction of 81 novel
viral genomes and the monitoring of viral abundance and diversity. And the
metatranscriptomics study on the microbial population of the granulation reactor
allowed for the tracking of transcribed viral genes. It was observed that there was
relatively higher expression of filamentous phage genes during the granule
development phase and high abundance of filamentous phage during the granule
maintenance phase. Supporting the notion that filamentous phage might play an
important role in biofilm development and stability.